<?php
/**
 * Created by PhpStorm.
 * User: Administrator
 * Date: 2017/11/16
 * Time: 11:19
 */

namespace Home\Controller;

class JSSDK {

    private $appId;

    private $appSecret;

    public function __construct($appId, $appSecret) {

        $this->appId = $appId;

        $this->appSecret = $appSecret;

    }

    public function getSignPackage() {

        $jsapiTicket = $this->getJsApiTicket();

        $url = "http://$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";

        $timestamp = time();

        $nonceStr = $this->createNonceStr();

        // 这里参数的顺序要按照 key 值 ASCII 码升序排序

        $string = "jsapi_ticket=$jsapiTicket&noncestr=$nonceStr&timestamp=$timestamp&url=$url";

        $signature = sha1($string);

        $signPackage = array(

            "appId"     => $this->appId,

            "nonceStr"  => $nonceStr,

            "timestamp" => $timestamp,

            "url"       => $url,

            "signature" => $signature,

            "rawString" => $string

        );

        return $signPackage;

    }

    private function createNonceStr($length = 16) {

        $chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";

        $str = "";

        for ($i = 0; $i < $length; $i++) {

            $str .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);

        }

        return $str;

    }

    private function getJsApiTicket() {

        // jsapi_ticket 应该全局存储与更新，以下代码以写入到文件中做示例

        $data = json_decode(file_get_contents("jsapi_ticket.json"));

        if ($data->expire_time < time()) {

            $accessToken = $this->getAccessToken();

            $url = "https://api.weixin.qq.com/cgi-bin/ticket/getticket?type=jsapi&access_token=$accessToken";

            $res = json_decode($this->httpGet($url));

            $ticket = $res->ticket;


            if ($ticket) {

                $data->expire_time = time() + 7000;

                $data->jsapi_ticket = $ticket;

                $fp = fopen("jsapi_ticket.json", "w");

                fwrite($fp, json_encode($data));

                fclose($fp);

            }

        } else {

            $ticket = $data->jsapi_ticket;

        }

        return $ticket;

    }

    private function getAccessToken() {

        // access_token 应该全局存储与更新，以下代码以写入到文件中做示例

        $data = json_decode(file_get_contents("access_token.json"));

        if ($data->expire_time < time()) {

            $url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=$this->appId&secret=$this->appSecret";
            $res = json_decode($this->httpGet($url));
            $access_token = $res->access_token;

            if ($access_token) {

                $data->expire_time = time() + 7000;

                $data->access_token = $access_token;

                $fp = fopen("access_token.json", "w");

                fwrite($fp, json_encode($data));

                fclose($fp);

            }

        } else {

            $access_token = $data->access_token;

        }

        return $access_token;

    }

    private function httpGet($url) {

        $curl = curl_init();

        curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);

        curl_setopt($curl, CURLOPT_TIMEOUT, 500);

        curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);

        curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);

        curl_setopt($curl, CURLOPT_URL, $url);

        $res = curl_exec($curl);

        curl_close($curl);

        return $res;

    }

}